For many applications, it is desirable to have available an aircraft which can remain in the air for a long time and can fly at great altitudes. Furthermore, for particular purposes, there is a need for an aircraft which, in the event of a structural collapse of the aircraft and an associated fall, can be brought to the ground safely with as little damage as possible.
For example, use is made of aircraft for air monitoring and air reconnaissance which fly at very great heights and have very long flight times and in the process are intended for example to be able to take aerial photographs. In an alternative application, an ultralight aircraft can also be referred to as a high altitude platform. A high altitude platform can be used for monitoring purposes (traffic, event, weather) or, at an appropriate height, even for mobile communications without the delay known in the case of satellites.
Developed for such uses are, inter alia, aircraft which have very long flight times and can operate at great altitudes. Solar cells, which are attached to the airfoils, are usually used for the energy supply. Such aircraft are usually operated in an unmanned state and can have a corresponding size. These aircraft are sometimes referred to as drones. Such aircraft are usually delicate or have a lightweight structure and can be damaged in the event of strong air turbulence, which, in an extreme case, can result in the flying qualities being lost, such that the aircraft falls or individual components can come away from the aircraft and can drop down.